The +VDD1 and +VDD3 power rails rise during cold boot of the module PMIC, so both rails are stable before the SoC is taken out of the reset and before code execution starts. They are intended to activate voltage regulators on the expansion board so system devices can be available when the module code execution begins.

Both the +VDD1 and +VDD3 rails can be used directly for powering system components or enabling voltage regulators and supplies on the expansion board if the maximum current limits in the table below are not exceeded.

If the power consumption of external peripherals is not known, do not use the +VDD1 and +VDD3 power rails directly.